Why does an open soda go flat according to the principles of the Ideal Gas Law?

• A. The temperature of the soda decreases, trapping more carbon dioxide in the liquid.
• B. Carbon dioxide gas escapes from the liquid into the atmosphere, reducing its concentration in the soda.
• C. The pressure inside the soda increases, causing more carbon dioxide to dissolve.
• D. The volume of the soda decreases, increasing the solubility of carbon dioxide.

Answer: (B)

Verified step by step guidance

1. Recall that the Ideal Gas Law is given by the equation \(P \times V = n \times R \times T\), where \(P\) is pressure, \(V\) is volume, \(n\) is the number of moles of gas, \(R\) is the gas constant, and \(T\) is temperature.
2. Understand that in a closed soda bottle, carbon dioxide gas is dissolved in the liquid under pressure, establishing an equilibrium between the dissolved gas and the gas phase above the liquid.
3. When the soda is opened, the pressure above the liquid decreases to atmospheric pressure, disrupting the equilibrium and causing carbon dioxide gas to escape from the liquid into the atmosphere.
4. As carbon dioxide escapes, the number of moles of dissolved gas (\(n\)) in the liquid decreases, which is consistent with the Ideal Gas Law as the gas leaves the solution to balance the pressure difference.
5. This loss of dissolved carbon dioxide reduces the carbonation, making the soda go flat because less gas remains dissolved in the liquid.